FIGURE 6.

Role of Fli-I and BAF53 in cyclical, estrogen-dependent recruitment of SWI/SNF complex to the pS2 promoter. A and B, chromatin immunoprecipitation assays were performed with MCF7 cells as in Fig. 5 after transfection with siRNA against Fli-I (siFli-I) or siNS and treatment with E2 for the indicated times. Results shown are from a single experiment and are representative of at least two independent experiments. C, ChIP assays were performed in MCF7 cells transfected 72 h previously with siFli-I or siNS. E2 or vehicle was added 45 or 90 min before cross linking of chromatin, ChIP was performed with the indicated antibodies, and the presence of the pS2 promoter region in the immunoprecipitates was determined by qPCR (first two panels). Fli-I, ERα, BRG1, BAF53, and β-actin protein levels from total cell lysates of MCF7 cells were determined by immunoblot (third panel). Fli-I mRNA levels were determined by qRT-PCR (fourth panel). D, ChIP assays were performed as in A, but siRNA against BAF53 was substituted for siRNA against Fli-I (third panel). BAF53 mRNA levels were determined by qRT-PCR (first panel). BAF53, ERα, Fli-I, and BRG1 protein levels from total cell lysate of MCF7 cells were determined by immunoblot (middle panel).